Dormant grass is usually described as grass that is “sleeping.” It’s not in stasis or frozen and it can still grow and will still need water and other nutrients, but the rate at which this occurs is slowed dramatically. If your lawn has gone dormant and you aren’t sure whether you should add water or not (and you want it to stay dormant to prevent damage), the information below should help you determine if adding water is necessary and how much to add if so.
Should You Water Dormant Grass? (The Short Answer)
Does dormant grass need water? Yes, dormant grass needs water but it needs less water than grass that is actively growing and reproducing. Further, you don’t want to water your lawn too much, especially during a period of dormancy brought on by hot weather, as this may wake the grass and break the safe dormant state.
First: Why Has Your Grass Gone Dormant?
Grass will enter a dormant state to protect itself from damage or a period in which it lacks the resources to grow and reproduce as usual. Three situations will typically trigger this dormancy.
- Excessively Hot Weather – Most grass has an ideal temperature range for growth as well as temperatures above which it will enter a dormant state until things cool off. This is, in most cases, consistent temperatures above 85F, though this can be more or less depending on the grass type.
- Excessively Cold Weather – It may seem obvious for grass to enter a dormant state when temperatures are below freezing, but grass will often enter dormancy well before this point. If grass is not dormant when it freezes, it can be severely damaged. This is why most grass types that can withstand a freezing winter will enter a dormant state as soon as temperatures cool off to a regular 45F or below.
- Drought or Inadequate Moisture – The final condition in which grass will enter a dormant state is if it has had inadequate moisture for 2 or more consecutive weeks. Inadequate moisture for most grass types is equal to about 1/4” or less of rain or irrigation per week.
Situations in Which Watering Dormant Grass is Absolutely Necessary
While it’s not always necessary to water your lawn while it is dormant, and most lawn owners will not need to, there are a few scenarios in which watering your lawn during dormancy will keep it alive.
High Temperatures and Drought-like Conditions
There is only one common situation in which watering dormant grass is necessary: high temperatures and a lack of rain for 2 weeks. If you live where temperatures have reached above 85F and they stay there or above every day, all day long, it’s likely that your grass is dormant.
If, in addition to these consistently high temperatures and dormant state, there has been no rain in the past 2 weeks, you should water your lawn. To keep your lawn in this safe, dormant state and conserve resources, you should only water your lawn about 1/4” every week or 1/2” in total every other week.
This watering should be done early in the morning, ideally in the hour before sunrise, and is the equivalent of watering your lawn with a sprinkler or drip irrigation system for 5 to 15 minutes on the lowest settings.
Long-term Drought
The other situation that you may encounter when your lawn may need to be watered during a period of dormancy is dormancy caused by drought. If your lawn hasn’t had any water in 2 or 3 weeks, it may go dormant at any temperature.
When this happens, it’s important to water your lawn a small amount every two weeks to keep it alive, yet dormant. You can achieve this state by watering your lawn the same way you would during a period of high temperatures and drought-like conditions, as described above.
When You Might Not Need to Water Dormant Grass
Does dormant grass need water? Yes, but it needs so little with such a low frequency that it will likely get this water from a natural source. While it will never hurt your lawn to add a half-inch of water every 2 weeks, even when the grass is dormant, there are a few situations when you may want to hold off.
Your Lawn Already Has Enough Water
If your lawn has any sort of standing water, you do not need to and should not add more. When it is excessively hot and drought has recently been broken by heavy rain, it can take several days or up to a week for this water to seep into the ground and be adequately absorbed by your lawn.
In a case like this, your lawn should be able to “wake up” and come out of dormancy. If it does not green up after 2 weeks and it has been getting adequate moisture, you may have dead grass. We have written a more comprehensive guide on how to determine if your grass is dead or dormant.
Your Lawn Is Covered in Frost or Snow or the Ground is Frozen
If your lawn is covered in frost, snow, or the ground is frozen then your lawn has access to plenty of moisture. Adding more or watering your lawn while it’s in this state will not help it and will only create an additional layer of ice.
There is a Drought or Local Water Limit
Should you water dormant grass during a drought? If the water in your area needs to be used for another purpose or it is illegal to water your lawn, do not water your lawn. Your grass has entered a state of dormancy in preparation or a long stretch without resources. Most lawns, especially those with resilient, cool-season grass types will be able to survive several months without added moisture.
Temperatures Have Suddenly Risen or Lowered
If it was very cold and now temperatures have suddenly gotten significantly warmer, or if it was unbearably hot and now things have cooled off to a better range for growing grass (80F or less), then you should not water your lawn. This is because if you water your lawn now, it will likely wake up, as ideal temperatures and a sudden excess of water tend to wake up dormant grass.
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